JP4424188B2 - Control device for internal combustion engine - Google Patents

Description

  The present invention relates to a control device for an internal combustion engine, and more particularly, to a control device that performs stop control for operating an internal combustion engine for a predetermined period after an ignition switch is turned off.

  Japanese Unexamined Patent Publication No. 2000-104651 (Patent Document 1) discloses an ignition device for operating an engine for a certain period of time even after an ignition switch is turned off. The ignition device includes an engine control unit (Engine Control Unit: hereinafter referred to as “ECU”) that controls ignition of a spark plug and fuel injection, an ignition switch, and an ECU that supplies / cuts off operating power to the ECU. A relay, an ignition coil and a spark plug, and an ignition coil relay are provided. The ignition switch and the ECU relay are arranged in parallel between the battery power source and the ECU. The ignition coil relay is disposed between the battery power source and the ignition coil, and receives an operation command from the ECU.

  In this ignition device, power is supplied to the ignition coil via an ignition coil relay controlled by the ECU. Then, after the ignition switch is turned off, the ignition plug is ignited a predetermined number of times, and then the ignition coil relay is turned off by the ECU.

According to this ignition device, since the ignition plug is ignited a predetermined number of times after the ignition switch is turned off, the injected fuel remains in the engine cylinder without being burned. And deterioration of exhaust properties can be prevented (see Patent Document 1).
JP 2000-104651 A JP-A-6-137197 JP 2000-87770 A JP-A-11-107794 JP-A-3-78563 JP-A 63-34241

  However, the driver of the vehicle recognizes that the engine stops when the ignition switch is turned off. When the accelerator pedal is depressed after the ignition switch is turned off, the ignition device described above does not suck the engine. Since the amount of air increases and ignition continues, the engine output increases against the driver's intention.

  Accordingly, the present invention has been made to solve such a problem, and an object of the present invention is to provide an internal combustion engine based on an accelerator operation during stop control for operating the internal combustion engine for a predetermined period after the ignition switch is turned off. It is an object of the present invention to provide a control device for an internal combustion engine that prevents the output fluctuation of the engine.

  According to the present invention, the control device for an internal combustion engine is a control device for an internal combustion engine whose output fluctuates according to the operation of an accelerator pedal, and is a stop control that operates the internal combustion engine for a predetermined period after the ignition switch is turned off. The control means which invalidates operation of an accelerator pedal at the time of execution of is provided.

  Preferably, the control means prohibits taking in the accelerator opening signal that changes in accordance with the amount of operation of the accelerator pedal when executing the stop control.

  Preferably, the control means sets the value of the accelerator opening signal that changes according to the operation amount of the accelerator pedal to a minimum value when the stop control is executed.

  Preferably, the control means controls the opening of the throttle valve for adjusting the intake air amount of the internal combustion engine to be constant when the stop control is executed.

  Preferably, the control means controls the opening degree of the throttle valve to the state when the ignition switch is turned off when the stop control is executed.

  Preferably, the control means controls the opening degree of the throttle valve to a state at the time of idling of the internal combustion engine when the stop control is executed.

  Preferably, the control means controls the injection of the fuel supplied to the internal combustion engine to be constant when the stop control is executed.

  Preferably, the control means stops injection of fuel supplied to the internal combustion engine when the stop control is executed.

  In the control apparatus for an internal combustion engine according to the present invention, the control means executes stop control for operating the internal combustion engine for a predetermined period after the ignition switch is turned off. The control means invalidates the operation of the accelerator pedal that causes the output fluctuation of the internal combustion engine when the stop control is executed, so that the output of the internal combustion engine increases even if the accelerator pedal is depressed during the execution of the stop control. Never do.

  Therefore, according to the present invention, the output fluctuation of the internal combustion engine unexpected by the driver can be prevented.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

  FIG. 1 is an overall configuration diagram of an engine system controlled by a control device according to an embodiment of the present invention. Referring to FIG. 1, this engine system 10 includes an engine 20, an ignition device 30, an intake duct 35, an injection device 40, an air cleaner 45, a fuel tank 50, a delivery pipe 60, and a fuel pump 70. ECU 80, throttle valve 90, and accelerator pedal 95 are provided.

  The engine 20 generates power for a vehicle on which the engine system 10 is mounted. The ignition device 30 includes an igniter that generates a high voltage, and an ignition plug (none of which is shown) that generates a discharge spark using the high voltage from the igniter, and ignites the engine based on a control command from the ECU 80. The air-fuel mixture in 20 cylinders is burned.

  The injection device 40 includes an injector that injects fuel into fine particles, and injects the fuel supplied from the delivery pipe 60 into the air supplied from the intake duct 35 to the engine 20 based on a control command from the ECU 80. As a result, a mixture of air and fuel is generated, and the generated mixture is supplied into the cylinder of the engine 20.

  The intake duct 35 is an intake pipe for supplying air to the engine 20. The throttle valve 90 is disposed in the intake duct 35 and adjusts the amount of air supplied to the engine 20 based on an opening degree command CTL from the ECU 80. The air cleaner 45 is connected to the intake duct 35 and removes foreign matters contained in the air supplied to the engine 20 via the intake duct 35.

  The fuel tank 50 is a tank for storing fuel, and the delivery pipe 60 is a fuel supply pipe for supplying the fuel in the fuel tank 50 to the injection device 40. The fuel pump 70 is an electric pump and is disposed in the delivery pipe 60. The fuel pump 70 operates based on an operation command from the ECU 80, and supplies the fuel in the fuel tank 50 to the injection device 40 via the delivery pipe 60.

  The ECU 80 controls the operation of the throttle valve 90, the ignition device 30, and the injection device 40 based on the accelerator opening signal AP indicating the opening of the accelerator pedal 95 and the signal NE indicating the rotational speed of the engine 20, and the engine 20 Is operated at a desired rotational speed. The opening of the accelerator pedal 95 is detected by an accelerator opening sensor (not shown), and the rotation speed of the engine 20 is detected by a rotation speed sensor (not shown).

  Further, when the engine 20 is stopped, the ECU 80 performs stop control for operating the ignition device 30 and the injection device 40 for a predetermined period after the ignition switch is turned off. This will be described in detail later.

  In the engine system 10, an air-fuel mixture of air supplied from the intake duct 35 and fuel supplied from the fuel tank 50 is generated by the injector 40, and the air-fuel mixture is supplied to the engine 20. The ignition device 30 is ignited at a predetermined timing based on a control command from the ECU 80, and the air-fuel mixture supplied to the engine 20 is combusted.

  Further, ECU 80 generates an opening degree command CTL for throttle valve 90 based on accelerator opening degree signal AP from accelerator pedal 95, and outputs the generated opening degree command CTL to throttle valve 90. Thereby, the intake amount of the engine 20 is adjusted in accordance with the depression amount of the accelerator pedal 95, and the rotational speed of the engine 20 is controlled.

  FIG. 2 is a functional block diagram of a control device that controls engine system 10 shown in FIG. Referring to FIG. 2, the control device 100 includes an ignition switch 110, a main relay 120, an ignition / injection relay 130, an ignition device 30, an injection device 40, a pump drive relay 140, and a fuel pump 70. ECU 80, power supply line PL, and ground line SL.

  Power supply line PL is connected to a positive terminal of a battery (not shown, the same applies hereinafter), and ground line SL is connected to a negative terminal of the battery.

  Ignition switch 110 is disposed between power supply line PL and ECU 80, and is operated by a vehicle driver. Main relay 120 is arranged between power supply line PL and ECU 80, and supplies / cuts off electric power from power supply line PL to ECU 80. The main relay 120 includes a contact 122 and a coil 124, and performs an on / off operation using a magnetic force generated in the coil 124 when a current flows through the coil 124. That is, the main relay 120 is turned on when a current is flowing through the coil 124 and is turned off when a current is not flowing through the coil 124.

  Ignition / injection relay 130 is disposed between power supply line PL and ignition device 30 and injection device 40, and supplies / cuts off electric power from power supply line PL to ignition device 30 and injection device 40. The ignition / injection relay 130 includes a contact 132 and a coil 134, and performs an on / off operation using a magnetic force generated in the coil 134 when a current flows through the coil 134. The coil 134 has one end connected to a line connecting the contact 122 of the main relay 120 to the ECU 80 and the other end connected to the ground node 150.

  The ignition / injection relay 130 is driven by the output from the main relay 120. That is, when the main relay 120 is turned on, a current flows from the main relay 120 to the coil 134 of the ignition / injection relay 130 and the ignition / injection relay 130 is turned on. Further, when the main relay 120 is turned off, no current flows from the main relay 120 to the coil 134, so the ignition / injection relay 130 is turned off.

  The ignition device 30 is supplied with operating power from the power line PL via the ignition / injection relay 130. The ignition device 30 includes an igniter 32 and a spark plug 34. Igniter 32 operates based on a control command from ECU 80, and boosts the voltage received from power supply line PL via ignition / injection relay 130. The spark plug 34 generates a discharge spark for igniting the air-fuel mixture using the boosted voltage boosted by the igniter 32.

  The injection device 40 is supplied with operating power from the power line PL via the ignition / injection relay 130. The injection device 40 includes injectors 42 corresponding to the cylinders of the engine. Each injector 42 operates based on a control command from the ECU 80, and injects the fuel supplied from the fuel pump 70 into fine particles.

  Pump drive relay 140 is disposed between ignition switch 110 and fuel pump 70, and supplies / cuts off electric power from power supply line PL to fuel pump 70. The pump drive relay 140 includes a contact 142 and a coil 144, and performs an on / off operation using a magnetic force generated in the coil 144 when a current flows through the coil 144. The coil 144 has one end connected to the ignition switch 110 and the other end connected to the ECU 80.

  The pump drive relay 140 is operable when the ignition switch 110 is turned on, and is driven by the ECU 80 when the ignition switch 110 is turned on. When the ignition switch 110 is turned off, the pump drive relay 140 is also turned off in synchronization therewith.

  The fuel pump 70, which is an electric pump, receives operation power from the power line PL via an ignition switch 110 and a pump drive relay 140 connected in series. Then, when the pump drive relay 140 is turned on based on the operation command from the ECU 80, the fuel pump 70 operates by receiving power from the pump drive relay 140, and sends the fuel in the fuel tank 50 to the injection device 40. Supply.

  The ECU 80 receives the accelerator opening signal AP from the accelerator pedal 95 and the signal NE from the engine 20, and the opening degree of the accelerator pedal 95 and the rotational speed of the engine 20 indicated by the received accelerator opening signal AP and signal NE, respectively. Based on such conditions, the opening of the throttle valve 90, the ignition timing of the ignition device 30, and the injection timing of the injection device 40 are determined. The ECU 80 outputs an opening degree command CTL to the throttle valve 90 to control the opening degree of the throttle valve 90, and outputs control commands corresponding to the ignition and injection timings to the ignition device 30 and the injection device 40, respectively. The drive of the ignition device 30 and the injection device 40 is controlled. Further, the ECU 80 outputs an operation command to the pump drive relay 140 to drive the fuel pump 70.

  Further, ECU 80 performs stop control of engine 20 when ignition switch 110 is turned off by the driver of the vehicle. In this stop control, the ignition switch 110 is turned off in order to set an actuator (such as an intake / exhaust valve controlled by a variable valve timing (VVT)) that is operated by engine oil pressure to a predetermined position for the next engine start. After that, the engine 20 is operated only for a predetermined period.

  In other words, when ignition switch 110 is turned off, ECU 80 continues to drive ignition device 30 and injection device 40 for a predetermined time. Then, after elapse of a predetermined time, the ECU 80 stops the ignition device 30 and the injection device 40 and stops power feeding to the coil 124 of the main relay 120. Thereby, main relay 120 is turned off, and power supply from power supply line PL to ECU 80 is interrupted. That is, ECU 80 self-cuts off the power supply from power supply line PL.

  Here, during the stop control of the engine 20, the ECU 80 disables the operation of the accelerator pedal 95 by prohibiting the update of the accelerator opening signal AP from the accelerator pedal 95, and fixes the opening of the throttle valve 90. An opening signal CTL is output to the throttle valve 90. This is to prevent the output fluctuation of the engine 20 due to the accelerator pedal 95 being depressed during the stop control of the engine 20. That is, the driver of the vehicle recognizes that the engine 20 is stopped by turning off the ignition switch 110. However, the above-described stop control of the engine 20 operates the engine 20 for a predetermined period after the ignition switch 110 is turned off. Therefore, there is a possibility that the accelerator pedal 95 is depressed after the ignition switch 110 is turned off by a driver having the above recognition. If the accelerator pedal 95 is depressed, the throttle valve 90 is opened to increase the intake air amount of the engine 20 and the ignition device 30 and the injection device 30 are operating. Therefore, the rotational speed of the engine 20 increases. Therefore, as described above, during the stop control of the engine 20, the operation of the accelerator pedal 95 is invalidated and the opening of the throttle valve 90 is fixed.

  As a method of invalidating the operation of the accelerator pedal 95, the updating of the accelerator opening signal AP is prohibited, the intake of the accelerator opening signal AP from the accelerator pedal 95 is prohibited, or the accelerator opening signal AP is minimum. The value may be forcibly set. Regardless of the change in the accelerator opening signal AP, the opening command CTL to the throttle valve 90 is fixed to the value when the ignition switch 110 is turned off, or the opening command CTL corresponding to the idling state is forced. May be output.

  The ECU 80 invalidates the operation of the accelerator pedal 95 in order to prevent the output variation of the engine 20 due to the depression of the accelerator pedal 95 during the stop control of the engine 20, but does not depend on the operation of the accelerator pedal 95. Variations in the output of the engine 20 due to variations in the load of an air conditioner or the like are allowed. Thereby, the unexpected stall of the engine 20 by load fluctuations, such as an air-conditioner, is prevented.

  The ECU 80 constitutes “control means”.

  In this control device 100, when the ignition switch 110 is turned off, the pump drive relay 140 is turned off accordingly, and the fuel pump 70 is stopped. Then, ECU 80 performs stop control of engine 20 and further drives ignition device 30 and injection device 40 for a predetermined time. During the stop control of the engine 20, the fuel pump 70 is already stopped, but the remaining pressure of fuel in the delivery pipe 60 is supplied to the injection device 40.

  Here, during execution of the stop control of the engine 20, the ECU 80 prohibits updating of the accelerator opening signal AP from the accelerator pedal 95 and outputs a constant opening command CTL based on the fixed accelerator opening signal AP. The generated opening degree command CTL is output to the throttle valve 90.

  When a predetermined time elapses after the ignition switch 110 is turned off, the ECU 80 stops the operation of the ignition device 30 and the injection device 40 and stops the power supply to the coil 124 of the main relay 120. As a result, the main relay 120 is turned off and the ECU 80 is shut off by itself. Then, in conjunction with the main relay 120 being turned off, the ignition / injection relay 130 is turned off, and the power supply from the power line PL to the ignition device 30 and the injection device 40 is interrupted.

  FIG. 3 is a flowchart of stop control of engine 20 executed by ECU 80 shown in FIG. Note that the processing according to this flowchart is executed at a predetermined cycle. Referring to FIG. 3, ECU 80 determines whether or not ignition switch 110 is turned off based on the potential of the connection line to ignition switch 110 (step S10). When ECU 80 determines that ignition switch 110 is not turned off (NO in step S10), ECU 80 resets counter A to 0 (step S70). This counter A is a counter for measuring the execution time of the stop control of the engine 20. Then, when the counter 80 resets the counter A to 0, the process proceeds to step S80.

  On the other hand, when it is determined in step S10 that the ignition switch 110 is turned off (YES in step S10), the ECU 80 adds a counter A to time the time since the ignition switch 110 is turned off (step S20). . Note that when the ignition switch 110 is turned off, the fuel pump 70 stops.

  The ECU 80 prohibits the update of the accelerator opening signal AP received from the accelerator pedal 95 in order to prevent the output fluctuation of the engine 10 due to the operation of the accelerator pedal 95, and the throttle valve 90 regardless of the depression amount of the accelerator pedal 95. The opening degree of the throttle valve 90 is controlled so that the opening degree becomes constant (step S30).

  Next, the ECU 80 determines whether or not the counter A added in step S20 is equal to or greater than a value α corresponding to a predetermined time (step S40). If ECU 80 determines that counter A is greater than or equal to α (YES in step S40), ECU 80 stops outputting control commands to ignition device 30 and injection device 40, and ignition control by ignition device 30 and injection control by injection device 40 are performed. Is stopped (step S50). Thereafter, the ECU 80 turns off the main relay 120 and self-blocks (step S60), and ends a series of processes. When the main relay 120 is turned off, the ignition / injection relay 130 is turned off as described above, and power supply from the power supply line PL to the ignition device 30 and the injection device 40 is interrupted.

  On the other hand, when it is determined in step S40 that the counter A is less than α (NO in step S40), the ECU 80 determines that the predetermined time has not yet elapsed since the ignition switch 110 was turned off, and the ignition device The ignition control by 30 and the injection control by the injection device 40 are continuously executed (step S80).

  In step S30, instead of prohibiting the update of the accelerator opening signal AP received from the accelerator pedal 95, the ECU 80 prohibits the intake of the accelerator opening signal AP or the accelerator opening signal AP as described above. Processing for forcibly setting the minimum value in the AP may be performed. Alternatively, the ECU 80 performs a process of fixing the opening degree command CTL output to the throttle valve 90 to a value when the ignition switch 110 is turned off, or forcibly outputting the opening degree command CTL corresponding to the idling state. Also good.

  As described above, according to the control device 100 according to this embodiment, after the ignition switch 110 is turned off, stop control for operating the engine 20 for a predetermined period is executed. In the control device 100, since the operation of the accelerator pedal 95 is invalidated during the stop control of the engine 20, the opening degree of the throttle valve 90 is fixed and the stop control is performed after the ignition switch 110 is turned off. Even if the accelerator pedal 95 is inadvertently depressed by the driver, the output of the engine 20 does not increase. Therefore, overrun of the vehicle can be reliably prevented.

  Further, the control device 100 allows the output variation of the engine 20 due to the load variation of the air conditioner and the like not depending on the operation of the accelerator pedal 95 during the stop control of the engine 20, so that the unexpected engine stall due to the load variation of the air conditioner or the like. Can be prevented.

  In the above-described embodiment, the operation of the accelerator pedal 95 is invalidated during the stop control of the engine 20, and thereby the opening of the throttle valve 90 is fixed. However, the operation of the accelerator pedal 95 is invalidated. The fuel injection timing and the fuel injection amount from the injection device 40 may be controlled to be constant. Furthermore, during the stop control of the engine 20, the fuel injection from the injection device 40 may be controlled to stop. As a result, even in an engine system that controls output by controlling fuel injection, engine output fluctuations during engine stop control can be prevented.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and is intended to include meanings equivalent to the scope of claims for patent and all modifications within the scope.

1 is an overall configuration diagram of an engine system controlled by a control device according to an embodiment of the present invention. It is a functional block diagram of the control apparatus which controls the engine system shown in FIG. It is a flowchart of the engine stop control performed by ECU shown in FIG.

Explanation of symbols

  10 engine system, 20 engine, 30 ignition device, 32 igniter, 34 spark plug, 35 intake duct, 40 injection device, 42 injector, 45 air cleaner, 50 fuel tank, 60 delivery pipe, 70 fuel pump, 80 ECU, 90 throttle valve 95 accelerator pedal, 100 control device, 110 ignition switch, 120 main relay, 122, 132, 142 contact, 124, 134, 144 coil, 130 ignition / injection relay, 140 pump drive relay, PL power line, SL ground line.

Claims (8)

A control device for an internal combustion engine, the output of which varies according to the operation of an accelerator pedal,
Even after the ignition switch is turned off, ignition control and injection control are executed to stop the operation of the internal combustion engine for a predetermined period , and the operation of the accelerator pedal is invalidated , and the intake amount of the internal combustion engine is A control device for an internal combustion engine, comprising control means for controlling a throttle valve opening to be adjusted to a non-zero predetermined value .   2. The control device for an internal combustion engine according to claim 1, wherein when the stop control is executed, the control unit prohibits taking in an accelerator opening signal that changes in accordance with an operation amount of the accelerator pedal. 3.   2. The control device for an internal combustion engine according to claim 1, wherein the control means sets a value of an accelerator opening signal that changes according to an operation amount of the accelerator pedal to a minimum value when the stop control is executed. 3. Wherein, when the performance of the stop control, controls the opening of the throttle valve constant, the control apparatus for an internal combustion engine according to any one of claims 1 to 3.   5. The control device for an internal combustion engine according to claim 4, wherein, when the stop control is executed, the control unit controls the opening degree of the throttle valve to be in a state when the ignition switch is turned off.   5. The control device for an internal combustion engine according to claim 4, wherein the control means controls the opening of the throttle valve to a state when the internal combustion engine is idling when the stop control is executed. 6.   The control device for an internal combustion engine according to any one of claims 1 to 3, wherein the control means controls the injection of fuel supplied to the internal combustion engine to be constant when the stop control is executed.   The control device for an internal combustion engine according to any one of claims 1 to 3, wherein the control means stops injection of fuel supplied to the internal combustion engine when the stop control is executed.

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